Recommendation ITU-T Q.4163 (12/2023) Protocols for Kx interfaces for quantum key distribution networks Summary History FOREWORD Table of Contents 1 Scope 2 References 3 Definitions 3.1 Terms defined elsewhere 3.2 Terms defined in this Recommendation 4 Abbreviations and acronyms 5 Conventions 6 Kx interface 7 Signalling procedure 7.1 Signalling procedures for key relay 7.2 Signalling procedures for key supply notification 8 Signalling messages and parameters 8.1 Key relay message 8.2 Key relay completion notification message 8.3 Key supply notification message 8.4 Response to key supply notification message 9 Security considerations Appendix I Protocol implementation using the transmission control protocol Bibliography